(1) Field of the Invention
This invention relates to a guide rail lip for a passive seat belt system, and specifically to a guide rail lip equipped with clips as unitary members.
(2) Description of the Related Art
The use of a seat belt system has become popular in recent years, mainly, due to the mandatory requirement for the use of a seat belt system in an automotive vehicle such as automobile. Reflecting this move, there is an ever-increasing interest in passive seat belt systems which do not require much labor in fastening or releasing a webbing. This invention relates to a guide rail lip for a passive seat belt system. In order to facilitate the understanding of the present invention, the concept of a general passive seat belt system is described first of all with reference to FIG. 6. Numeral 1 indicates a webbing which is paid out from or taken up in a retractor 2 fixed on a seat 20. Designated at numeral 3 is an emergency release buckle (hereinafter referred to simply as "buckle"), in which a tongue attached to one end of the webbing 1 is inserted. Designated at numeral 4 is a movable anchor which is integral with the buckle 3. The movable anchor 4 travels, together with the buckle 3, through a guide rail 6 between an anchor base 5 arranged behind the seat 20 and the front end of the guide rail 6. In order to control the movement of the movable anchor 4, a front end switch 8 and an unillustrated rear end switch are provided at the front end of the guide rail 6 and within the anchor base 5 respectively. Designated at numeral 12 are brackets by which the guide rail 6 is mounted on a stationary base 10 of the vehicle. Numeral 91 indicates a drive member, such as wire, for driving the movable anchor 4, while numeral 9 designates a drive unit for taking up or pushing out the drive member 91. The operations of the drive member and drive unit are well known in the art and their detailed descriptions are omitted herein.
When the door is opened, the drive member 91 is pushed out from the drive unit 9 so that the movable anchor 4 is guided toward the front of the vehicle along the rail 6. As soon as the movable anchor 4 is brought into contact with the front end switch 8, the switch 8 stops the operation of the drive unit 9. Since the buckle 3 fixed integrally on the movable anchor 4 has also been brought to a front part of the stationary base, the webbing 1 has moved apart frontward from an occupant (not shown) so that the occupant is allowed to get off or get on the automobile easily.
When the occupant then gets on the automobile and closes the door, the drive unit 9 is actuated to take up the drive member 91, whereby the movable anchor 4 is then guided back to the anchor base 5 along the guide rail 6. Owing to the provision of the unillustrated rear end switch within the anchor base 5 as mentioned above, the operation of the drive unit 9 is stopped upon arrival of the movable anchor 4 at the anchor base 5. As a result, the webbing 1 restrains the body of the occupant as depicted in FIG. 6.
FIG. 7 is a cross-sectional view of the guide rail 6 taken in the direction of arrows VII--VII of FIG. 6. The guide rail 6 is mounted on the stationary base 10 of the vehicle by means of brackets 12. The movable anchor 4 is caused to move while being guided by the guide rail 6. Rubber-made lips 7,7 are attached to both sides of the guide rail 6 and are in contact with a stem 41 of the movable anchor 4. These lips 7,7 are provided to prevent the intrusion of foreign materials such as rail water and dust into the guide rail 6 and also to shield off the moving noise of the movable anchor 4.
FIGS. 8-10 illustrate a conventional lip structure and a method of its attachment. As shown in FIG. 8, longitudinal grooves 61,61 are formed centrally in both side walls of the guide rail 6 and matching longitudinal ridges 71,71 are formed at the corresponding parts of the lips 7,7. As depicted in FIG. 9, the ridges 71,71 of the lips 7,7 are fit in the corresponding grooves 61,61 of the guide rail 6 so that the lips 7,7 are attached to the guide rail 6. A clip 72 is additionally fit over the lips 7,7 to fix the lips 7,7 on the guide rail 6. FIG. 11 is a cross-sectional view taken in the direction of arrows XI--XI of FIG. 10. Instead of fitting together the guide rail and lips in the above manner, they may be put together by double-tack tapes and may then be fixed together by clips as depicted in FIGS. 10 and 11.
As has been described above, the structure and attachment method of such conventional lips do not permit easy assembly and requires rather many assembly steps, and may hence lead to an higher manufacturing cost.